Field of the Invention
The present invention relates to a method of isolating soyasaponin I from the whole part, especially the seed, of plants of Leguminosae except soybean.
Description of the Prior Art
Soyasaponin I is chemically expressed as 3-O-[.alpha.-L-rhamnopyranosyl(1.fwdarw.2)-.beta.-D-galactopyranosyl(1.fwd arw.2)-.beta.-D-glucuronopyranosyl]soyasapogenol B of the following structural formula: ##STR1##
The soyasaponin I is a valuable compound showing metabolic activity (Japanese Patent Laid-open No. 73025/1981), anti-thrombinomimetic activity (Japanese Patent Laid-open No. 95914/1982), etc. in vivo, which is known to be contained in soybean along with soyasaponins II, III, A.sub.1 and A.sub.2.
Now it has been found after diligent investigation that soyasaponin I is contained in the whole plant, especially in the seed of plants of Leguminosae except soybean, especially plants of Leguminosae Trifolium, Leguminosae Medicago, Leguminosae Astragalus, Leguminosae Vicia, etc. in larger quantities than in soybean.